Patent RU-2660820-C1 (RU)
Inventor: Kochetov Oleg Savelevich
IPC: G10K11/16
Filed: 2017-06-14
Granted: 2018-07-10
Abstract: FIELD: acoustics. 
     SUBSTANCE: invention relates to the industrial acoustics, particularly, to the broadband noise suppression, and can be used in all branches of the national economy during the production equipment noise suppression by the sound absorption method. Room acoustic enclosure contains frame, window and door openings, openings for luminaires, single piece sound absorbers and acoustic enclosures, made in the form of rigid and perforated walls, between which the multilayer sound absorbing element is arranged, which is made in the form of two layers: one of which, adjacent to the rigid wall, is the sound-absorbing, and the other, adjacent to the perforated wall, is made with perforation from the complex shaped sound-reflecting material, consisting of uniformly distributed hollow tetrahedrons. As the sound-reflecting material, the aluminum-containing alloys based material is used, with their subsequent filling with titanium hydride or air with density within 0.5…0.9 kg/m 3  with the following strength properties: compressive strength within 5…10 MPa, bending strength within 10…20 MPa, for example foamed aluminum, or the “Noise-stopper” type glass staple fiber based soundproofing plates with the material density of 60÷80 kg/m 3 , or the magnesia binder based material with reinforcing fiberglass cloth or glass-fiber mat. Single piece sound absorber consists of frame filled with sound absorbing material placed in protective shell. To the frame perforated stretching steel sheet is fixed. Frame can be made in the form of rectangular parallelepiped. Perforated stretching metal sheet has the following perforation parameters: holes diameter of 3÷7 mm, perforation percentage of 10÷15%. According to the form holes can be made in the form of round, triangular, square, rectangular or diamond-shaped profile holes, at that, in case of non-circular holes, as the conditional diameter the inscribed in the polygon circle maximum diameter should be considered. Either the single piece of sound absorber frame can be made spherical with the congruent to the framework internal spherical resonance cavity formed by the rigid continuous spherical shell, equidistant to the outer perforated spherical shell, at that, the space between the spherical shells is filled with sound absorbing material. Outer perforated spherical shell connection to the object, for example, the production room ceiling, is made by means of the resilient damping element, allowing the high-frequency oscillations damping and is pivotally connected to the made in the form of rod suspension, which one end is connected to the mounted on the resilient damping element hinge, and the other is connected to ring intended for its fixation on the object. By at least one bushing the spherical resonance cavity is rigidly connected to axial bore acting as the Helmholtz resonator neck, with the outer perforated spherical shell, and the space between them is filled with the sound absorber. 
     EFFECT: invention allows to improve the noise absorption efficiency. 
     1 cl, 6 dwg